[[REDACTED]]

Run node redacted.js [options] <filename> to execute the program. Any non-ancient nodejs version should be enough.

Options

• --no-execute: Perform the requested tasks but don't execute the program
• --dump-bytecode: Dump the generated bytecode
• --dump-ast: Dump the generated AST

The idea

The theme of the compo is "first-class comments". Redacted tries to accomplish this by offering mechanisms for manipulating the behaviour of the comments.

There is a suggested syntax that comments can use: [[TAG(arg1, arg2, arg2): Description]] or [[TAG: Description]]). Comments that don't match that structure are categprozed as 'naked' and can be handled with the corresponding handler.

The original idea included the ability to iterate the comments of a given function, and exposing the program state to the handler. Because of time and manpower limitations only this initial sketch is available.

Pseudo-BNF

During the writing of the parser we changed things a bit. This may not be 100% to the code.

literal := STRING | NUMBER
ident   := IDENT

simple_expr  := literal | ident | parenthesized_expr | lambda | block | cond | loop
expr         := assignment | call | field_access | simple_expr
assignment   := ((field_access | ident) ':=')+ (call | simple_expr)
field_access := (ident | parenthesized_expr) ('>>' ident)+
call         := (field_access | simple_expr) (field_access | simple_expr)+
sequence     := expr ('.' expr)* '.'?
parenthesized_expr := '(' sequence ')'
lambda := 'with' ident+ block
block  := 'do' sequence 'done'
cond   := 'if' expr 'then' expr 'else' expr
loop   := 'while' expr 'holds' expr

Caveats

• Numbers are only integers
• Strings have SQL-like quoting (that is hello 'world is written 'hello ''world')

Language

The language is dynamically typed, with the primitive types represented with proxies to javascript values.

Functions

Both "native" (written in the host language) and [[redacted]] functions have the following special properties:

• Function>>call: Calls the function without arguments
• Function>>with_args: A function that takes an array of arguments and calls the underlying function with those arguments

Arrays

Arrays are created with the array primitive. They have the following special properties:

• Array>>at: A function that takes a number and performs a dynamic property load for that index in the array
• Array>>set: A function that takes a number and a value and performs a dynamic property store for that index in the array
• Array>>length: The length of the array
• Array>>push: A function that takes an element and adds it to the end of the array
• Array>>pop: A function that removes the last element of the array and returns it

Objects

Objects are created with the obj>>call primitive.

Other primitives available

• <: A function that makes comparisons for host values. If the values cannot be compared returns none
• +: A function that add two numbers
• =: A function that makes an equality comparison.
• none: A kind of dummy value, our undefined
• print: Prints to the screen, our console.log
• str_concat: Mashes an arbitrary number of values into a string
• comments: The global CommentsController, it only has the category field: a function to retrieve or configure comment handlers

Examples

Some comentated code examples are available in the examples folder.